/*
 * Copyright 2011-2013 Blender Foundation
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

#include "stdosl.h"

shader node_refraction_bsdf(color Color = 0.8,
                            string distribution = "sharp",
                            float Roughness = 0.2,
                            float IOR = 1.45,
                            normal Normal = N,
                            output closure color BSDF = 0)
{
  float f = max(IOR, 1e-5);
  float eta = backfacing() ? 1.0 / f : f;
  float roughness = Roughness * Roughness;

  if (distribution == "sharp")
    BSDF = Color * refraction(Normal, eta);
  else if (distribution == "beckmann")
    BSDF = Color * microfacet_beckmann_refraction(Normal, roughness, eta);
  else if (distribution == "GGX")
    BSDF = Color * microfacet_ggx_refraction(Normal, roughness, eta);
}
